This invention is directed to a coupler for an irrigation system for progressive connection and disconnection with a series of risers or connectors along a pressurized pipe line for delivering liquid, under pressure, from the pipe line to the irrigation system. The coupler of the present invention is particularly useful with an irrigation system of the linear type where both ends of the system move over the field to be irrigated. Such a system is distinguished from those of the center-pivot type where one end of the system is pivotally mounted at a central location in the field for rotation of the system about a generally vertical axis at the pivot location.
More specifically, the present invention is particularly useful on linear systems having a liquid delivery apparatus for continuously delivering liquid from the pressurized pipe line to the irrigation system as the system moves over the field. Such systems are exemplified by those shown and described in U.S. Pat. Nos. 4,036,436 and 4,172,556, the entirety of which are incorporated herein by reference. A further example of such a system is that shown and described in U.S. patent application Ser. No. 06/161,678, filed June 23, 1980, of which this application is a continuation-in-part.
The primary object of the present invention is to provide such a coupler that is reliable and durable, that will operate repeatedly and for a long duration under conditions where sand and dirt are prevalent, and that will operate effectively and efficiently to open and close the valves within the risers under the liquid pressure with minimum spill and in a controlled manner to reduce the sudden impact of the liquid as would produce a water hammer upon operation of the valves.
Generally, the coupler of the present invention includes a conduit member operable relative a frame between a retracted disconnect position and an extended connect position. A sealing member is reciprocally mounted to the conduit member for engagement and disengagement with a riser. A valve operating means operates, in response to movement of the conduit member, to open and close the riser valve, such that partial extension of the conduit member engages the sealing member with the riser and further extension of the conduit member produces relative movement of the conduit and sealing members with said valve operating means opening said valve.
In a preferred embodiment of the invention, there are no sliding seals required to maintain a liquid seal between the riser and the coupler and between the relative moving members of the coupler so that sand and dirt have a minimal adverse effect on the coupler. The result is a coupler that is exceptionally dependable and reliable through long operation.
The invention will now be described in more detail with reference to the drawings, but first the drawings themselves will be described briefly.